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Biomedical subjects

E Fernandez

Publications and source records attributed to E Fernandez.

At least 199 records · Page 11Linked to original sources
PubMed1992

Levocarnitine acetyl prevents cell death following long-term section of the vagus nerve in rats.

Levocarnitine acetyl has previously been found to significantly prevent axotomy-induced cell death in the spinal cord motor nucleus 9 and 12 months after section of the sciatic nerve in rats. In the present paper, the effects of levocarnitine acetyl on axotomy-induced cell death in the brain stem motor nuclei 90 days after section of the vagus nerve were studied. The right vagus nerve was cut at the neck. To prevent regeneration, a 5 mm-long segment of the vagus nerve was excised and the distal stump was displaced caudally. After surgery, a group of rats (n = 6) was treated with levocarnitine acetyl dissolved in the drinking water (75 mg/kg/day) (Group I). A second group of operated rats (n = 4) received drinking water alone. (Group II). Ninety days postoperatively, in the rats of both groups the proximal nerve stump of the vagus nerve was injected with horseradish peroxidase to label retrogradely the brain stem motoneurons of the dorsal motor vagal and the ambiguus nuclei. The brain stem nuclei were also labelled by horseradish peroxidase in three unoperated control rats (Group III). In the Group II rats, the number of horseradish peroxidase-labelled motoneurons of the dorsal motor vagal nucleus was found to be significantly smaller than in either the Group I (p < 0.01) or the Group III (p < 0.02) animals. In the Group I rats, the number of motoneurons of the dorsal motor vagal nucleus was not significantly smaller compared to the Group III rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcarnitine↗
PubMed1992

Indications and results of hepaticojejunostomy in benign strictures of the biliary tract.

The postoperative and late results of 99 patients with benign strictures of the biliary tract are presented. Patients were classified according to Bismuth into 24 cases with lesion type I, 36 cases with type II, 35 cases with type III and 4 patients with type IV. All were submitted to hepaticojejunostomy with a long Roux-en-Y loop. The etiology of the strictures varied according to the type of stricture. In patients of type I, inflammatory and iatrogenic causes were observed. Among type II and III patients, previous cholecytocholedochal fistulas were the main cause, together with accidental section or ligature of the common bile duct. Operative mortality was absent in strictures of types I and II, while it was around 25% in cases of types III and IV. At late control, the best results were seen among patients with strictures of types I and II. We believe that the main factor determining the early and late outcome of these cases with benign strictures is the location of the stricture and the quality of the proximal duct.

Adult↗
PubMed1992

alpha-Glucosidase and N-acetyl-beta-D-glucosaminidase isoenzymes in serum.

Using different conditions for incubation and fluorometry with 4-methylumbelliferylglycosides as substrates, we demonstrated the presence of acid alpha-glucosidase, "renal" alpha-glucosidase, N-acetyl-beta-D-glucosaminidase A, and N-acetyl-beta-D-glucosaminidase B in freshly drawn normal human serum. The acid alpha-glucosidase enzymatic activity was determined at pH 4.0 in 0.1 mol/L Tris reagent, whereas the renal isoenzyme activity was determined at pH 5.6 in presence of 0.05 mol/L turanose reagent. N-Acetyl-beta-D-glucosaminidases A and B were determined by their different behaviors on heating. The corresponding reference intervals for each enzyme were calculated from results for 40 controls: acid alpha-glucosidase (0.024 +/- 0.010 U/L), renal alpha-glucosidase (0.035 +/- 0.012 U/L), N-acetyl-beta-D-glucosaminidase A (10.2 +/- 2.9 U/L), and N-acetyl-beta-D-glucosaminidase B (4.4 +/- 2.1 U/L).

Acetylglucosaminidase↗
PubMed1991

The vasculature of the rat penis: a scanning electron microscopic and histologic study.

As a basis for understanding the mechanism of erection in an animal model frequently used in research in reproductive biology, the angioarchitecture of the penis of the rat has been described using scanning electron microscopy. Study of the penile vasculature of the rat indicates that the corpora cavernosa penis and the corpus spongiosum are independent erectile tissues, each with its own arterial and venous vessels. The large vascular spaces and abundant smooth muscle of the penile crura are compatible with its role in regulating blood flow to more distal penile tissues. Helicine arteries of the crura, but not the parent deep penile artery or arteries elsewhere, have muscular cushions in their walls. The venous drainage of the penile crura is via subtunical veins which are thought to be compressed during erection to elevate pressure within the penis. Large, paired cavernous veins drain the shaft of the penis. A unique method for inhibiting blood flow from the penis is indicated by the division of the cavernous veins into smaller channels prior to joining the subtunical venous plexus. Erectile tissue in the bifid origins of the corpus spongiosum has abundant cavernous muscle, while in the remainder of the corpus spongiosum little smooth muscle lines the cavernous spaces. The cavernous spaces on either side of the urethra coalesce to form vessels, each of which communicates with cavernous spaces in the glans. In addition, a bypass of the glans is effected by communication of these vessels directly with the deep dorsal vein. The apparent absence of muscular pads in vessels of the spongiosum, the relative paucity of cavernous smooth muscle, and the ample venous drainage provided by the deep dorsal vein may account for the lack of a venous occlusive mechanism similar to that of the corpora cavernosa penis.

Animals↗
PubMed1991

Distribution and origin of neuropeptide Y-immunoreactive fibers in the penis of the rat.

The present study investigated the distribution of neuropeptide Y-immunoreactive fibers to the penis of the rat. In the corpora cavernosa penis, a dense plexus of fibers was associated with arteries, intrinsic cavernosal muscle, and veins, including the deep dorsal vein. In the corpus spongiosum, immunoreactive fibers were present around vascular smooth muscle and at the periphery of the acini of the paraurethral glands. Immunohistochemistry of penile neurons identified by retrograde tracer injection into the penis indicates that about 5% of the penile neurons in the pelvic plexus contained the neuropeptide while larger percentages of penile neurons in the sympathetic chains were immunoreactive for neuropeptide Y. Chemical and surgical sympathectomy greatly reduced the neuropeptide Y- and catecholamine-containing fibers in the erectile tissue but had no clear effect on the neuropeptide Y fibers around the paraurethral glands; a tissue that is not innervated by adrenergic fibers. It is concluded that (1) the widespread distribution of neuropeptide Y indicates that it may function in the control of penile blood flow, (2) with the possible exception of the paraurethral glands, the sympathetic chain is the most likely source of neuropeptide Y fibers in both erectile bodies of the penis, and (3) this peptide may play a role in the secretory functions of the paraurethral glands.

Animals↗
PubMed1991

Experimental studies on spinal cord injuries in the last fifteen years.

Experimental studies on spinal cord (SC) injuries published from 1975 to 1989 in some of the most widely circulating neurosurgical journals were reviewed. The relatively large number of animal species utilized as well as the intensely variable dynamic or static methods employed to induce SC injury represent elements of confusion more than objective necessities in this field of research. In fact, the objective of SC injury research should be to solve the problem of severe SC injuries by either preventing and/or repairing SC damage, rather than looking for modalities to provoke a large spectrum of SC injuries with the result of establishing a correlation between for example, the clinical picture and trauma magnitude. It should be time to study all variables and treatments mainly in only one experimental model. The rat with a permanent paraplegia should represent such a model; the abdominal aorta occlusion for 45 minutes, distal to the renal arteries in rabbits should be the experimental model of choice for ischaemia. If a significant result, such as reversing permanent paraplegia, were obtained in rats, it would be logical to repeat the study in higher mammals and if successful, in humans. For the last decade of this century it is necessary to further study all the mechanisms implied in secondary SC damage as well as to attempt to repair definitive SC damage by using grafts and enhancing the potential regenerative ability of the SC with known and new growth factors. Presently, methylprednisolone, dexametasone, thiopental, naloxone, and hypothermia seem to have some clinical potentials that require studies in humans.

Animals↗
PubMed1991

Monoclonal antibody against murine T cell receptor V alpha 14 cross-reacts with human CD3 epsilon and detects disulfide-linked dimeric form.

A monoclonal antibody against V14+ alpha-chain of murine T cell receptor (TCR) was established by fusing spleen cells from a rat immunized with a soluble chimeric TCR/IgG3 protein containing murine TCR V alpha 14J alpha 281 in place of the VHDHJH of an IgG3. lambda 1, and subjected to screening on a human transfectant (Jurkat variant) expressing the murine V14J281 alpha-chain. The anti-mouse V alpha 14 antibody precipitated TCR alpha beta molecules from Triton X-100-solubilized extracts of 125I-labeled murine thymocytes and spleen cells. Unexpectedly, the antibody showed cross-reactivity to the human CD3 epsilon molecule and detected a disulfide-linked 20 kDa dimeric form of human CD3 epsilon, which is a novel family component of the CD3 complex and is associated closely with the CD3 zeta-zeta homodimer as well as TCR alpha beta or TCR gamma delta.

Animals↗
PubMed1991

Sustained improvement in gas exchange after negative pressure ventilation for 8 hours per day on 2 successive days in chronic airflow limitation.

Negative pressure ventilation (NPV) was applied for 6 to 8 h/day for 2 consecutive days in 13 patients with severe airflow limitation and chronic respiratory failure. After cessation of NPV, the mean arterial blood gases were improved in 10 patients, and this improvement was sustained for the nex 2 days in eight patients, for 3 days in seven patients, and was still present in four patients on the fourth day. Respiratory muscle strength improved in all patients, but there was no relationship between the increase in strength and sustained improvement in gas exchange. Ventilation and respiratory pattern were unchanged in all patients, but the mean VD/VT fell and VA rose while the VO2 and VCO2 fell. The ventilatory responses to hypoxia and hypercapnia increased in patients who demonstrated sustained improvement in blood gases. The mechanism underlying the sustained improvement in gas exchange following NPV is not clear but is likely multifactorial.

Aged↗
PubMed1991

An "open-transformed scale" for correcting ceiling effects and enhancing retest reliability: the example of pain.

The use of closed scales (with anchors at each end) to measure pain was found to produce ceiling effects characterized by a deceleration of ratings toward the upper end of the scale. This was consistent with previous research. Apart from producing nonlinear functions, the closed scale also limited test-retest reliability because of subjects' tendencies to correct their distorted ratings in subsequent trials. However, an open-ended scale coupled with transformation of reported ratings into a decile scale virtually eliminated the ceiling effect, thus producing consistently linear functions and maximizing test-retest reliability. This finding may have implications for the measurement of other sensory and psychological phenomena, especially those in which the property evaluated varies in a continuous fashion.

Analysis of Variance↗
PubMed1991

Levocarnitine acetyl promotes the regeneration of peripheral sensory axons and reduces the hypertrophy of axotomized spinal cord motoneurons in rats.

In previous studies, the neurotrophic action of levocarnitine acetyl on the regeneration of the sciatic nerve in rats has been demonstrated. The present study investigated the particular effect of levocarnitine acetyl on the initial stages of sciatic nerve regeneration. In the first 8 days after sciatic nerve lesion caused by crushing (Group A) or cutting (Group B), the rats of both groups were divided into 2 subgroups: treated rats received daily intraperitoneal levocarnitine acetyl (a megadose of 100 mg in saline solution); untreated rats only received saline solution. Treatment started on the day of operation. The regeneration growth rate of sensory fibres was studied using the pinch test. The size of the axotomized spinal motoneurons was studied using retrograde axonal tracers (horseradish peroxidase or Fast blue). The results showed that: (a) levocarnitine acetyl promoted the elongation of sensory fibres in the first 8 days following the crushing or sectioning of the sciatic nerve, but the data were only statistically significant (p less than 0.01) for the first 3 days after crushing; (b) levocarnitine acetyl accelerated the velocity of sensory fibre regeneration when compared to untreated rats by 16% in the first 3 days after nerve crushing, by 14% in the first 4 days after nerve section, and by 32% from the 5th to the 8th day after nerve section; (c) levocarnitine acetyl promoted a significant reduction in spinal motoneuron hypertrophy when compared to untreated rats at both 4 and 8 days after sciatic nerve section.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcarnitine↗
PubMed1991

Pharmacokinetics of vancomycin in patients undergoing hemodialysis with polyacrylonitrile.

The pharmacokinetics of vancomycin in patients undergoing dialysis with cuprophane membranes are well known, however little has been reported of the use of polyacrylonitrile membranes in dialysis. We studied, in a crossover design, eight dialysis patients (7 men, 1 woman) aged 30 to 66 years who prospectively received 1 gram of vancomycin i.v. before first dialysis and were subsequently hemodialyzed with cuprophane every second day for a total of three times. A month later trial was repeated using polyacrylonitrile. A mono-compartment model was used to calculated pharmacokinetic parameters. Mean +/- standard deviation of vancomycin clearance varied from 5.2 +/- 2.1 ml/min in the interdialysis period to 9.7 +/- 2.7 ml/min during dialysis with cuprophane and to 58.4 +/- 15.6 ml/min during dialysis with polyacrylonitrile (p less than 0.001). Vancomycin half-life varied from 71.5 +/- 23.0 to 35.9 +/- 9.8 and to 6.1 +/- 1.4 hours, respectively (p less than 0.001). Fractional removal of vancomycin increased from 4% using the cuprophane dialyzer to 34% using the polyacrylonitrile dialyzer (p less than 0.001). Serum vancomycin levels at 100 and 168 hours were higher with cuprophane than with polyacrylonitrile (7.0 +/- 2.2 vs 3.9 +/- 1.2 micrograms/ml) (p less than 0.001). Moreover, the mean levels at 100 hours were suboptimal on polyacrylonitrile. Approximately 208 +/- 53 mg of vancomycin were removed during one polyacrylonitrile dialysis. Thus, those patients who undergo dialysis with polyacrylonitrile and are treated with vancomycin may need supplementary doses post dialysis or to lessen dosage intervals than those traditionally used for dialysis patients since clearance of the drug is significantly higher than with cuprophane dialyzers. Continuous monitoring of vancomycin levels is also recommended.

Acrylic Resins↗